In Summorum pontificum, our Holy Father makes clear in the first Article that any priest may, without any permissions, say a Private Mass whenever he wishes in the Extraordinary Form.
Does "Private Mass" have a legal meaning in terms of the legislation surrounding the current post-conciliar liturgical texts? Or in the current Code of Canon Law?
Does the term "Private Mass", when applied by legislative documents (such as a motu proprio) to the EF, mean what it meant in the official documents of the age when the EF was the ordinary form of the Roman Rite, back in the days of the great Rubricians, the era of O'Connell et al.?
If so, which of the eight different meanings found in those documents does it point to? Or, when there is a lack of specificity in a legal formula, does the subject of the law have the right to the least constricting of the possibilities?*
For Info: O'Connell gives these definitions of "Private Mass", with footnotes pointing to the legislative basis which each has. I simplify:
A Mass in a private place
A Mass neither High nor Sung
A non-conventual Mass
A Mass neither Sung nor Conventual
A Mass not of obligation
A Mass detached from the Liturgy of the Day (e.g. the Palm Sunday Procession)
A Requiem neither sung nor conventual nor 'privileged'
A Votive, whether High, Sung, or Low, celebrated for a cause which is not public and grave
* This sentence is the question which I am most interested in having an informed answer to.